Node.js · Middle · Question 56 of 75

How do you test an Express app's endpoints without starting a real server on a fixed port?

1Endpoints can only be tested manually
2Mock the http module completely
✓Correct answer: Pass the app to a library like Supertest, or start it on port 0 and call it with fetch

Explanation

Port 0 lets the OS pick a free port, so tests can run in parallel. Export the app separately from the listen() call to make this easy.

Further reading

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